Quick answer: Moss and algae grow on shaded, damp walkways across Metro Vancouver and make them dangerously slippery when wet. The most effective fix is a combination of power washing to remove growth, an eco-friendly treatment to slow it from returning, and regular sweeping to keep debris from holding moisture. Most strata buildings need this done at least once a year, ideally in early fall.
Vancouver’s mild, wet weather is perfect for moss and algae. A walkway that’s fine in August can turn green and slick by November. For strata councils, that’s more than a cosmetic issue. A slippery common-property walkway is a safety risk for residents and visitors, and a potential liability for the corporation.
Why Moss and Algae Keep Coming Back
Moss and algae need three things: moisture, shade and something to hold on to. Most strata properties have all three:
- North-facing paths that rarely get direct sun
- Areas under trees where leaves and needles hold moisture
- Porous concrete and pavers with texture that spores can grip
- Poor drainage spots where water pools after rain
- Joints between pavers where soil and debris collect
Power washing removes what you can see, but spores remain in the surface pores. Without treatment and ongoing maintenance, growth typically returns within one or two wet seasons.
The Real Risk: Slip and Fall Exposure
Algae in particular forms a thin film that’s almost invisible on wet concrete. People walking on a familiar path don’t expect it to be slick, which is exactly when falls happen. Common high-risk spots include:
- Outdoor stairs and ramps
- Paths between parkade exits and building entrances
- Pool decks and courtyard patios
- Garbage and recycling routes used daily
Under BC’s Occupiers Liability Act, whoever controls the property has a duty to take reasonable care that people using it are reasonably safe. Keeping a documented maintenance record of walkway cleaning shows the council is taking that responsibility seriously.
How Professional Moss and Algae Removal Works
- Power sweep first. Leaves, needles and loose debris are removed so they don’t get pushed into joints or drains.
- Pre-treat heavy growth. An eco-friendly cleaner is applied to loosen thick moss and kill algae at the surface.
- Power wash. Pressure is matched to the surface. Concrete can take more; pavers and stamped concrete need care so joint sand and finishes aren’t blown out.
- Rinse and inspect. The crew checks for missed patches and areas where water pools.
- Apply a post-treatment if appropriate. A follow-up treatment can slow regrowth through the wet season.
Timing: When to Book
Early fall is the best time for most Metro Vancouver properties. Surfaces are still dry enough to work on, growth from summer is visible, and cleaning before the rains removes the base that winter growth builds on. A second, lighter pass in spring helps buildings with heavy shade or tree cover.
What Councils Can Do Between Cleanings
- Trim branches that shade walkways to let in more light
- Keep gutters and drains clear so water doesn’t spill onto paths
- Schedule regular power sweeping during leaf season
- Ask your caretaker to flag new green patches before they spread
- Consider anti-slip coatings on outdoor stairs that stay wet
Frequently Asked Questions
Will power washing alone get rid of moss permanently?
No. It removes visible growth, but spores remain. Combining washing with a treatment and regular maintenance gives much longer-lasting results.
Can power washing damage pavers?
It can if pressure is too high or the nozzle is held too close. Joint sand can also be washed out. A professional crew adjusts pressure and may recommend re-sanding joints afterward.
Are moss treatments safe for pets and landscaping?
Eco-friendly products are available that are much gentler on pets, people and plants than harsh chemical treatments. Ask your contractor what they use.
How much of the property should be done at once?
It’s usually most efficient to clean all walkways, stairs and patios in one visit, then spot-treat the problem areas in spring.
Keep Your Walkways Safe Through the Wet Season
EcoPlanet Property Services helps strata councils across Greater Vancouver keep walkways, stairs and courtyards clean and safe with power sweeping, power washing and eco-friendly treatments. Request a free quote or call 604-565-5238 before the rain sets in.
